const getCurrentCityName = function() {
    return new Promise((resolve, reject) => {
        let myCity = new BMap.LocalCity();
    myCity.get((result) => {
        let geoc = new BMap.Geocoder();
        geoc.getLocation(result.center, (rs) => {
        // rs 中携带着所有的定位信息，这里只获取了城市(city)和所在的区(district)
        let addComp = rs.addressComponents;
        let result = addComp.city + addComp.district;
        resolve(result);
        });
        }, {enableHighAccuracy: true});
    });
    }
